HEMA 2: Hemostasis & Vascular System Lecture Review

A comprehensive set of flashcards covering key concepts and details related to Hemostasis and the Vascular System that students need to know for their examination.

What is the process responsible for confining a clot to the site of injury?

Fibrinolysis

Which component is considered the 'ON SWITCH' for the Extrinsic Pathway?

Tissue Factor

Primary hemostasis primarily involves which two components?

Platelets and Vascular system

What is the goal of Secondary Hemostasis?

Formation of a stable fibrin clot

Which stage of hemostasis is described as a 'rapid and short-lived response'?

Primary Hemostasis

What is the main enzyme of the fibrinolytic system?

Plasmin

Inadequate hemostasis leads to what condition?

Hemorrhage

Which vascular layer anchors the blood vessel to surrounding tissues?

Tunica Externa (Adventitia)

Which layer contains smooth muscle cells?

Tunica Media

The vascular intima is mainly composed of which cell type?

Endothelial cells

In a healthy state, what is the role of endothelial cells?

Anticoagulant

Which substance secreted by endothelial cells acts as a potent vasodilator?

Prostacyclin (PGI_2)

What is the role of Nitric Oxide (NO) in hemostasis?

Induces vasodilation and inhibits platelet activation

Which glycosaminoglycan enhances the activity of Antithrombin?

Heparan sulfate

Thrombomodulin acts as a cofactor in the activation of which protein?

Protein C

What does the Protein C pathway specifically digest?

Factors V and VIII

Which enzyme cleaves ultra-large vWF multimers?

ADAMTS-13

Where is Von Willebrand Factor (vWF) stored in endothelial cells?

Weibel-Palade bodies

What is the primary initiator of the extrinsic coagulation cascade?

Tissue Factor (Factor III)

What is the function of Tissue Factor Pathway Inhibitor (TFPI)?

Limits activation of the TF:VIIa:Xa complex

Platelets originate from the cytoplasm of which bone marrow cell?

Megakaryocyte

What is the primary regulator of platelet production?

Thrombopoietin (TPO)

Where is the primary source of Thrombopoietin located?

Liver

What is endomitosis in megakaryocytes?

DNA replication without cytokinesis

Which maturation stage of megakaryocytes is the largest?

MK-III (Megakaryocyte)

What are the membrane-lined channels in platelets called?

Demarcation Membrane System (DMS)

How many platelets does a single megakaryocyte typically shed?

2,000–4,000

What is the average lifespan of a circulating platelet?

8–9 days

What is the normal reference range for platelets?

150–400 × 10^9/L

Where is one-third of the body’s platelets sequestered?

Spleen

What is the 'Control Center' for platelet activation?

Dense Tubular System (DTS)

Which structure maintains the platelet's discoid shape?

Microtubules (Tubulin)

The peripheral zone of a platelet includes what?

Glycocalyx and plasma membrane

How many Alpha granules are typically found in a single platelet?

50–80

Which protein is found in Platelet Alpha granules?

Fibrinogen and vWF

Which of the following is found in Platelet Dense granules?

ADP and ATP

What does the mnemonic KAPASA refer to?

Contents of Alpha granules

Which receptor binds to vWF in high shear stress?

GP Ib/IX/V

Which receptor binds directly to collagen?

GP VI

What is the major aggregation receptor that binds fibrinogen?

GP IIb/IIIa

Which enzyme converts Arachidonic Acid into Prostaglandin Endoperoxides?

Cyclooxygenase (COX)

What does Thromboxane A2 (TXA2) promote?

Aggregation and vasoconstriction

What shape change occurs when a platelet becomes activated?

Disc-shaped to spherical with pseudopods

Aspirin inhibits platelet function by acetylating which enzyme?

Cyclooxygenase

Which agonist binds to the P2Y1 and P2Y12 receptors?

ADP

Which receptor-ligand interaction inhibits platelet activation?

Prostacyclin (PGI_2)-IP3

What amino acid sequence in fibrinogen is targeted by GP IIb/IIIa?

RGD (Arginine-Glycine-Aspartate)

What acts as the 'glue' between platelets and collagen?

Von Willebrand Factor (vWF)

What does the 'Release Reaction' refer to?

Secretion of granule contents during activation

Most coagulation factors are synthesized in which organ?

Liver

Which coagulation factor is NOT synthesized in the liver?

Tissue Factor (Factor III)

What are coagulation factors that circulate in an inactive form called?

Zymogens

Which coagulation factor is known as 'Fibrinogen'?

Factor I

Which coagulation factor is known as 'Prothrombin'?

Factor II

Which coagulation factor is a transglutaminase?

Factor XIII

What does the 'Intrinsic Tenase' complex consist of?

IXa + VIIIa + Ca + PL

What does the 'Prothrombinase' complex consist of?

Xa + Va + Ca + PL

Which factor is responsible for cross-linking fibrin?

Factor XIII

What does the mnemonic 'Foolish People Try Climbing…' help remember?

Names of the coagulation factors

What is the final stage of hemostatic activation?

Fibrinolysis

Plasminogen is converted to Plasmin by which activator?

Tissue Plasminogen Activator (TPA)

What allows plasminogen to bind to lysine residues on fibrin?

Kringles

What is the primary inhibitor of TPA and UPA?

Plasminogen Activator Inhibitor-1 (PAI-1)

When does fibrinolysis usually begin?

Several hours after clot formation

What is the vitamin deficiency that causes Scurvy?

Vitamin C

Which disorder is characterized by 'corkscrew hairs'?

Scurvy

What is Solar purpura primarily due to?

Lack of collagen support for small blood vessels

What condition involves the deposition of misfolded proteins?

Amyloidosis

What are 'Stress platelets'?

Marked larger platelets with ribosomes and RER

Immune Thrombocytopenic Purpura (ITP) is caused by autoantibodies against what?

Platelet surface glycoproteins

In Acute ITP, what is often the platelet count?

What triad does Hemolytic Uremic Syndrome (HUS) present with?

Hemolytic anemia, Renal failure, Thrombocytopenia

What is 'Typical' HUS most often associated with?

Shiga toxin from E. coli O157:H7

What is Disseminated Intravascular Coagulation (DIC) characterized as?

Consumptive coagulopathy

Which condition is due to clonal proliferation of megakaryocytes?

Essential Thrombocythemia

What is the platelet count typically in Essential Thrombocythemia?

1 million/μL

Which symptom describes throbbing pain in hands and feet in ET?

Erythromelalgia

Reactive Thrombocytosis can be caused by which conditions?

Iron deficiency anemia

What deficiency is characteristic of Bernard-Soulier Syndrome?

GP Ib/IX/V

Which stage of hemostasis involves blood vessels and platelets?

Primary

What does 'Thrombocytopoiesis' refer to?

Platelet production

Which hemostatic factor is Extrinsic?

Tissue Factor (TF)

What differentiates a 'white clot' from a 'bulky red clot'?

White clots are platelets/vWF; red clots have fibrin and RBCs.

Which cytokine acts with TPO for stem cell differentiation?

IL-11

Which molecule mediates the switch from mitosis to endomitosis in megakaryocytes?

TPO

What is the MPV (Mean Platelet Volume) of a normal platelet?

8–10 fL

Which system allows endocytosis and secretion for alpha-granules?

Surface Connecting Canalicular System (SCCS)

Which type of receptor is essential for initial platelet adhesion?

GP Ib-IX-V

What is the significance of platelet 'satellitism'?

Artifact related to EDTA-induced antibody effects

What is the primary test for high-dose Heparin therapy?

Activated Clotting Time (ACT)